Diamond

Diamond is generally the most valuable jewel found in Castlevania. It is often found in a ring, which is sometimes called the Diamond Ring, and is associated with the Light attribute, healing and Defense.

It's first appearance was in Symphony of the Night as a "Highly Valuable Ring". It could be sold to the Master Librarian for 20,000 Gold, with the highest value for any jewel ring, being more valuable than an Opal (5,000 G). A Diamond is extremely rarely dropped by the Jewel Sword (if ever).

The Diamond is also the most valuable gem in Harmony of Dissonance. It is worth 1,000 G (which is considerably less in proportion to the other gems as compared to other games), which is more valuable than a Ruby (600 G).

Because Diamond is the hardest natural substance known to exist, any piece of equipment that is made of it tends to give more defense than any other of that type of equipment that is not supernaturally enhanced. The Diamond Plate is the most durable non-enchanted armor found in whatever game it is found in. Charlotte Aulin has a "diamond set" that maximizes her Defense. It consists of the Diamond Corset (+32) for the body, Diamond Shoes (+6) for the legs, Diamond Tiara (+10) for the head, and the Diamond Brooch (+5) for the Accessory.